Grid for protecting rontgen images against secondary rays



M. LOEBELL Filed March 29. 1924 v w 2 w/ Aug. 25, 1925..

GRID P03 PROTECTING R6NTGEN IMAGES AGAINST SECONDARY/RAYS Ema l... 25, 1925.-

.U'NI'TED srArEs PATENT OFFICE. i MAUBJGE mum, on zumsmm, 0x10.

can: roe. raomcrme Riemann mans AGAINST SECONDARY RAYS.

' Application flledmamas, 1924 Serial n. 702,995.

;T0 all whom it may comm:

Be it known that I, MAURICE Lon'nnLL, a citizen of the United States of America, and a resident of Zanesville, county of Muskingum and State of Ohio, have invented certain new and useful Improvements in Grids for Protecting Rontgen Images Against Secondary Rays, of which the following is a full and clear specification.' I

This invention has relation to that type of grid composed of a multiplicity of extremely thin layers of substances pervious to the Riintgen rays and impervious thereto, the pervlous layers alternating with the impervious layers or thicknesses, the grid being so constructed that the layers are presented edgewise to the Rontgen tube, so that the primary rays will pass directly through the pervious layers to the photographic plate or the fluoroscopic screen, and the secondary rays, striking the plate at an oblique angle to the primary rays, will be broken up and absorbed by the metallic barriers extending through the grid. The object of the present invention is to simplify the method of making such a grid, and to produce a-grid of minimum weight and Without mechanical devices or attachments to render the same useful, that will be highly efiicient in destroying and absorbing the secondary rays and eliminate the distortion resulting from curved grids and grids operated by mechanical devices and attachments preventin maximum proximity of grid to film an requiring a minimum of exposure, as more fully hereinafter set forth; In the drawing, Fig. 1 is a perspective view of a sheet of paper or celluloid for making the pervious layers; 7

Fig. 2 is a similar view of said sheet coated on each side with a layer of colloid material containing salts of a heavymetal; Fig. 3 is 'a perspective view, of a slab made up of narrow strips of the coated material shown in Fi 2; Fig. 4 is a vertica cross-sectional view through a fragment of the slab shown in Fig. 3; 9

- Fig. 5 is a plate or sla broken away;

Fig. 6 is a view similar to Fig. 5 showing a superposed-plate arrangement.

erspective view of a complete l; with the varnish coating In constructing my grid, I refer to proceed specifically as follows: l coat a sheet of celluloid 10 or paper or other substance pervlous to the Riintgen rays, on both surfaces, With a very thin layer of colloid material 11 into which the salts of a heavy metal, such as silver bromide or iodide, or pulverized metal, is incorporated, the colloidal material being applied with a brush or otherwise. After this sheet is dried, I

cut it into strips of required length and width and glue those strips, face-to-face, together by means of shellac or other ad'- hesive substance pervious -to Rontgen rays, thus building up a slab or plate of the desired width and thickness, the layers of celluloid or other pervious material alternating with the layersof metalliferous colloid material, these layers having their edges at the face of the plate or slab.

The plate or slab thus built up is dried under pressure in a suitable frame or press, and, when the plate is preferably dried, the

surfaces are scraped, sand-papered and polished; then varnish 12 is applied to the plate, preferably three coats, and then the plate is polished again. This varnish acts not only as an adhesive for binding the edges together, but also as an absorbent of an almost unappreciable amount of second-' ary radiation from the grid layers. The resulting product is a hard smooth slab Or plate, and it will be understood, of course,

that the plate is made flat and further that the strips of celluloid or, paper may be wound spirally with of course the metallif erous colloid material between the layers, s? asto thereby produce a circular slab or p ate.

It is obvious that, as shown in Fig. 6, two of the slabs or plates herein described may be arranged one upon the other, with the layers running at right-angles to each other, if desired. This superposed arrangement of the plates will be advantageous in that the secondary rays from whatever source they emanate will be'entirely'destroyed by the impervious barriers embodied in each grid. It will be further understood that, instead of mixing a metallic salt with 001- loidal materials, I may employ powdered metal of high atomic weight mixed with an adhesive substance such as glue, shellac, etc.; and it will be obvious further that the salts of heavy metal may be mixed with 7 ing strip; of material pervious to Rontgen carryin th sides with a colloidal substance the salts of a heavy metal, drying the strips thus coated, gluing to ether a multi licity of these strips face-toace, and then nishmg the plate or slab thus formed by polishing the same.

2. The method herein described of making a Rontgen ray grid consisting in coating strips of material pervious to Rontgen rays on both sides with a colloldal substance rays on carrying the salts of a heavy metal, drying the strips thus coated, gluing to ether a multiplicity of these strips face-toace, and then finishing the plate or slab thus formed by polishing the same, said late before the finishing step being provide wlth a coatmg of varnlsh or the hke.

3. A Rontgen ray grid composed of a multiplicity of alternating layers of material pervious to Rontgen rays and material impervious to Rontgen rays, the latter being in the form 0 a colloidal substance mixed with salts of a heavy metal.

4. ARontgen ray grid composed of a multiplicity of alternating layers of mate- 'rial pervious to Rontgen rays and material impervious to Rout en ra s, the latter bein in the form 0 a co oidal substance mixed with salts of a heavy metal, the late thus formed being coated with varnis the like and finished by polishing.

5. A Rontgen ray grid composed of a multiplicity of independent alternating layers 0 material pervious to Rontgen rays and material impervious to Rontgen rays, the latter being in the form of metal mixed in an adhesive substance spread between the pervious 7 layers and adhering thereto in order to fasten them together and thus form a unitary mass.

6. A Rontgen ray grid composed of a v multiplicity of separate alternating layers of material pervious to Riintgen rays and material impervious to Rontgen rays, the latter being in the form of a metal mixed in an adhesive substance placed between the pervious layers and adhering thereto in order to fasten them together and thus form a unitary mass of minimum weight and permitting close proximity of object to the photographic plate.

In testimony whereof I hereunto afiix my signature.

MAURICE LOEBELL, M. D. 

